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#ifndef OT_GLYF_PATH_BUILDER_HH
#define OT_GLYF_PATH_BUILDER_HH
#include "../../hb.hh"
namespace OT {
namespace glyf_impl {
struct path_builder_t
{
hb_font_t *font;
hb_draw_session_t *draw_session;
struct optional_point_t
{
optional_point_t () {}
optional_point_t (float x_, float y_) : has_data (true), x (x_), y (y_) {}
operator bool () const { return has_data; }
bool has_data = false;
float x = 0.;
float y = 0.;
optional_point_t lerp (optional_point_t p, float t)
{ return optional_point_t (x + t * (p.x - x), y + t * (p.y - y)); }
} first_oncurve, first_offcurve, last_offcurve;
path_builder_t (hb_font_t *font_, hb_draw_session_t &draw_session_)
{
font = font_;
draw_session = &draw_session_;
first_oncurve = first_offcurve = last_offcurve = optional_point_t ();
}
/* based on https://github.com/RazrFalcon/ttf-parser/blob/4f32821/src/glyf.rs#L287
See also:
* https://developer.apple.com/fonts/TrueType-Reference-Manual/RM01/Chap1.html
* https://stackoverflow.com/a/20772557 */
void consume_point (const contour_point_t &point)
{
bool is_on_curve = point.flag & glyf_impl::SimpleGlyph::FLAG_ON_CURVE;
optional_point_t p (font->em_fscalef_x (point.x), font->em_fscalef_y (point.y));
if (!first_oncurve)
{
if (is_on_curve)
{
first_oncurve = p;
draw_session->move_to (p.x, p.y);
}
else
{
if (first_offcurve)
{
optional_point_t mid = first_offcurve.lerp (p, .5f);
first_oncurve = mid;
last_offcurve = p;
draw_session->move_to (mid.x, mid.y);
}
else
first_offcurve = p;
}
}
else
{
if (last_offcurve)
{
if (is_on_curve)
{
draw_session->quadratic_to (last_offcurve.x, last_offcurve.y,
p.x, p.y);
last_offcurve = optional_point_t ();
}
else
{
optional_point_t mid = last_offcurve.lerp (p, .5f);
draw_session->quadratic_to (last_offcurve.x, last_offcurve.y,
mid.x, mid.y);
last_offcurve = p;
}
}
else
{
if (is_on_curve)
draw_session->line_to (p.x, p.y);
else
last_offcurve = p;
}
}
if (point.is_end_point)
{
if (first_offcurve && last_offcurve)
{
optional_point_t mid = last_offcurve.lerp (first_offcurve, .5f);
draw_session->quadratic_to (last_offcurve.x, last_offcurve.y,
mid.x, mid.y);
last_offcurve = optional_point_t ();
/* now check the rest */
}
if (first_offcurve && first_oncurve)
draw_session->quadratic_to (first_offcurve.x, first_offcurve.y,
first_oncurve.x, first_oncurve.y);
else if (last_offcurve && first_oncurve)
draw_session->quadratic_to (last_offcurve.x, last_offcurve.y,
first_oncurve.x, first_oncurve.y);
else if (first_oncurve)
draw_session->line_to (first_oncurve.x, first_oncurve.y);
else if (first_offcurve)
{
float x = first_offcurve.x, y = first_offcurve.y;
draw_session->move_to (x, y);
draw_session->quadratic_to (x, y, x, y);
}
/* Getting ready for the next contour */
first_oncurve = first_offcurve = last_offcurve = optional_point_t ();
draw_session->close_path ();
}
}
void points_end () {}
bool is_consuming_contour_points () { return true; }
contour_point_t *get_phantoms_sink () { return nullptr; }
};
} /* namespace glyf_impl */
} /* namespace OT */
#endif /* OT_GLYF_PATH_BUILDER_HH */
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